Larval fish distribution and abundance of the western Ross Sea

Ichthyoplankton samples were obtained during the Italian Antarctic Oceanographic Cruise carried out in the western Ross Sea in November-December 1994. The present study focused on improvement of the knowledge of the larval fish community in relation to its distribution and relative abundance. A midwater trawl (Hamburg Plankton Net) was used to collect samples at 26 stations. Larval and juvenile specimens of twentyone species belonging to six families (Artedidraconidae, Bathydraconidae, Channichthyidae, Macrouridae, Nototheniidae and Paralepididae) were collected from surface to 380 m depth. Mean relative abundance of larval fish in the whole area was about 2.7 specimens / 1000 m3 of sea water filtered. The upper 100 m of the water column showed the greatest species diversity and abundance. Postlarvae and juveniles of Pleuragramma antarcticum were the most abundant, followed by larval and postlarval specimens of Chionodraco sp. It was noteworthy the high number of Trematomus lepidorhinus (570 larvae) found in a single station off Terra Nova Bay. Our data give evidence of a great species diversity of the larval fish community in the western Ross Sea and show a greater abundance of fish larvae in inshore than in offshore waters.